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Topic: Optimization/Minimization of multiple argument function
Replies: 0

 sprl111 Posts: 1 Registered: 5/11/13
Optimization/Minimization of multiple argument function
Posted: May 11, 2013 2:27 AM

Hello,

I have this function, ptrans[n_, k_, h1_, h2_, fm_, em1_, f_, t0_], that I'm trying to minimize with respect to h1 & h2. The other parameters/arguments are provided constant values. At first I was using unconstrained optimization placing constants or constant lists for all arguments excpet h1/2. Also, I had h1 and h2 as a list called h but I could not get the minimization functions to feed h into the function. I kept getting errors saying, in essence, that h was not provided with a value. So, I made h two scalars h1 & h2 and then had the same problem. So then I tried constrained optimization placing == constraints on all the arguments except the h1 & h2. I'm still getting the same type of error. It is saying, "Symbol::argx: Symbol called with 0 arguments; 1 argument is expected". so basicially, near as I can tell the function is not getting fed numbers for the h1/h2 optimization variables. I'm using FindMinimum[] for the optimization.

Here's the last rendition that I tried,

FindMinimum[{ptrans[nn, kk, h1, h2, ffmm, emm1, ff, tt0][[7]],
nn == n, kk == k, ffmm == fm, emmm1 == em1, ff == f,
tt0 == t0}, {{h1, 1.0}, {h2, -1.0}} ]]

Earlier I was trying,

FindMinimum[ptrans[2, 0, h, fm, em1, f, t0][[7]], {h, {1.0, -1.0}} ]

So, I'm looking at the tutorials on optimization and am seeing all the examples only had arguments that were optimization parameters. Maybe that is the problem? Maybe Mathematica can't optimization a multiple paramater/argumement function unless all the arguments are optimization variables?

Anyone have any ideas/solutions?

Thanks you.